IEP train door mechanism

py_megapixel · 21 Oct 2019

I noticed while travelling on a class 80x (didn't get the number) that, when the train reaches a certain speed, a small metal block pushes the sliding pocket doors slightly outwards, with a rather distinctive "clunk." Then, when the train stops, this block appears to be pulled back in, and the door moves inwards.

This video shows departing from a red signal, accelerating and then immediately arriving in a station. I have held the camera such that the doors can be seen:

Any idea why it does this? Is it something to do with permitting emergency egress or something?

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FQTV · 21 Oct 2019

If it’s the same thing that Javelins do, I’ve always assumed that it was something to do with preparing the pocket doors for external pressure changes such as tunnels and passing trains.

I’d be interested to learn of a definitive explanation too, though.

EE Andy b1 · 21 Oct 2019

As far as i know it's the doors sealing themselves fully from the outside. The Voyagers have something similar but on them a rubber seal inflates to seal the doors but there getting a bit worn out now.

zebedee104 · 21 Oct 2019

FQTV said:
If it’s the same thing that Javelins do, I’ve always assumed that it was something to do with preparing the pocket doors for external pressure changes such as tunnels and passing trains.

It is the same thing that the Javelins do, but with the added bonus of 80Xs releasing the seal before the train comes to a standstill, so the door can open as soon as it’s released instead of the few-second wait on the 395.

alxndr · 21 Oct 2019

They all do that as far as I've seen, bit disconcerting at first but you get used to it.

py_megapixel · 21 Oct 2019

FQTV said:
If it’s the same thing that Javelins do, I’ve always assumed that it was something to do with preparing the pocket doors for external pressure changes such as tunnels and passing trains.

EE Andy b1 said:
As far as i know it's the doors sealing themselves fully from the outside. The Voyagers have something similar but on them a rubber seal inflates to seal the doors but there getting a bit worn out now.

But why is this not a part of the door opening/closing procedure?
I assume it must be automatic from the point of view of the staff anyway, so wouldn't it make sense to just have it happen when a passenger pushes the door open button for the first time after the doors are released, then they seal themselves when the doors are closed for departure? That would presumably reduce wear & tear on the mechanism, as it wouldn't operate for stops at signals, or where a door is not opened by a passenger.

Pumbaa · 22 Oct 2019

Because as evidenced by 395s, they extend dwell times and can be disconcerting to non-regular passengers, as the door doesn’t seem to open after repeatedly pressing the open button.

Plus as mentioned the 22x family seem to have found a perfectly reliable solution, so I’d suggest the potential impact on wear and tear is not as great as you think.

Bald Rick · 22 Oct 2019

zebedee104 said:
It is the same thing that the Javelins do, but with the added bonus of 80Xs releasing the seal before the train comes to a standstill, so the door can open as soon as it’s released instead of the few-second wait on the 395.

I understood the 395s did the release below 8mph.

There was an article about this whole subject by Roger Ford in a Modern Railways when the Javelins were introduced. The principle is exactly the same as on certain trains in Japan.

zebedee104 · 22 Oct 2019

Bald Rick said:
I understood the 395s did the release below 8mph.

There was an article about this whole subject by Roger Ford in a Modern Railways when the Javelins were introduced. The principle is exactly the same as on certain trains in Japan.

Afraid it doesn’t. Passengers sit there jabbing the buttons after the beep on 395s. It’s then several seconds before the seal releases and the door opens.

mark-h · 22 Oct 2019

Could there be some integration with the passenger information system to only release the seal when approaching a station? Obviously it would have to be overridden by a door release elsewhere if the PIS is confused.

IEP train door mechanism

py_megapixel

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alxndr

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py_megapixel

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